Information communication system, information communication method, node apparatus and recording medium

1. An information communication system in which a content is distributed and stored by an overlay network configured by a plurality of node apparatuses including a first node apparatus and which comprises a center server configured to manage the content to be submitted to the overlay network, the information communication system comprising: the first node apparatus comprising a first controller configured to control the first node apparatus to: assign content identification information, which identifies the content on the overlay network, to the content; divide the content into a plurality of chunks; assign chunk identification information and sequence number to each of the plurality of chunks; create hash value related to the plurality of chunks: create meta-information including the chunk identification information, the sequence number and the hash value, the meta-information being assigned the content identification information and being to be used in searching the content to the overlay network; transmit the created meta-information to the center server; receive the meta-information and an electronic signature verifying the meta-file from the center server; and permit the received meta-information to be acquired on the overlay network; and the center server comprising a second controller configured to control the center server to: receive the meta-information from the first node apparatus; determine whether the received meta-information is proper meta-information; and transmit the electronic signature to the first node apparatus of a transmission source of the received meta-information in response determining that the received meta-information is proper meta-information.

2. The information communication system according to claim 1 , wherein the first controller controls the first node apparatus to: create chunk information checking whether the content to be submitted to the overlay network is altered; and create the meta-information that also includes the created chunk information.

3. The information communication system according to claim 1 , wherein the first node apparatus includes a first storage unit configured to store authentication information indicating that the submission of the content to the overlay network is permitted, and the first controller controls the first node apparatus to transmit the created meta-information and the authentication information stored in the first storage unit to the center server, and the second controller controls the center server to: receive the meta-information and the authentication information transmitted by the first node apparatus; and determine whether the received meta-information is proper meta-information, based on the received meta-information and the received authentication information.

4. The information communication system according to claim 1 , wherein the center server includes: a second storage unit configured to store the authentication information received by the second reception unit and the identification information included in the meta-information in association with each other; and the second controller controls to center server to: determine whether the received identification information is identification information being used in the overlay network, based on the identification information stored in the second storage unit, and create identification information different from the determined identification information in response to determining that the received identification information is identification information being used in the overlay network.

5. The information communication system according to claim 1 , wherein the center server includes: a second storage unit configured to store the authentication information received by the second reception unit and the identification information included in the meta-information in association with each other; and the second controller controls to: determine whether the received identification information is identification information being used in the overlay network, based on the identification information stored in the second storage unit; and transmit, to the first node apparatus, an instruction to create identification information different from the determined identification information in response to determining that the received identification information is identification information being used in the overlay network.

6. The information communication system according to claim 1 , wherein the plurality of node apparatus includes a second node apparatus comprising a third controller to control the second node apparatus to: acquire the meta-information based on the content identification information, acquire the chunk identification information included in the meta-information, and acquire the chunks of the content based on the acquired chunk identification information so that the chunk identification information of the chunks configuring the content is acquired in correspondence to the sequence numbers of the chunks.

7. An information communication method in an information communication system in which a content is distributed and stored by an overlay network configured by a plurality of node apparatuses including a first node apparatus and which comprises a center server that manages the content to be submitted to the overlay network, the information communication method comprising: assigning, by the first node apparatus, content identification information, which identifies the content on the overlay network, to the content; dividing, by the first node apparatus the content into a plurality of chunks; assigning, by the first node apparatus, chunk identification information and sequence number to each of the plurality of chunks; creating, by the first node apparatus, hash value related to the plurality of chunks; creating, by the first node apparatus, meta-information including the chunk identification information, the sequence number and the hash value, the meta-information being assigned the content identification information and being to be used in searching the content to the overlay network; transmitting, by the first node apparatus, the meta-information created by the first creation step to the center server; receiving, by the center server, the meta-information transmitted from the first node apparatus; determining, by the center server, whether the meta-information received by the first reception step is proper meta-information; transmitting, by the center server, an electronic signature to the first node apparatus which is a transmission source of the received meta-information in response to the determination that the meta-information received by the first reception step is proper meta-information; receiving, by the first node apparatus, the meta-information and the electronic signature verifying the meta-information, which are transmitted from the center server; and permitting, by the first node apparatus, the received meta-information to be acquired on the overlay network.

8. A node apparatus of an information communication system in which a content is distributed and stored by an overlay network configured by a plurality of node apparatuses including a first node apparatus and which comprises a center server that manages the content to be submitted to the overlay network, the first node apparatus comprising: a first controller configured to control the first node apparatus to: assign content identification information, which identifies the content on the overlay network, to the content; divide the content into a plurality of chunks; assign chunk identification information and sequence number to each of the plurality of chunks; create hash value related to the plurality of chunks; create meta-information including the chunk identification information, the sequence number and the hash value, the meta-information being assigned the content identification information and being to be used in searching the content to the overlay network; transmit the created meta-information to the center server; receive the meta-information and an electronic signature verifying the meta-information, which is determined to be proper by the center server, from the center server; and permit the received meta-information to be acquired on the overlay network.

9. A non-transitory recording medium storing a program causing a computer of a node apparatus, which is provided in an information communication system in which a content is distributed and stored by an overlay network configured by a plurality of node apparatuses including a first node apparatus and which comprises a center server that manages the content to be submitted to the overlay network, to execute: assigning, by the first node apparatus, content identification information; which identifies the content on the overlay network, to the content; dividing, by the first node apparatus, the content into a plurality of chunks; assigning, by the first node apparatus, chunk identification information and sequence number to each of the plurality of chunks; creating, by the first node apparatus, hash value related to the plurality of chunks; creating, by the first node apparatus, meta-information including the chunk identification information, the sequence number and the hash value, the meta-information being assigned the content identification information and being to be used in searching the content into the overlay network; transmitting, by the first node apparatus, the created meta-information to the center server; receiving, by the first node apparatus, the meta-information and an electronic signature verifying the meta-information, which is determined to be proper by the center server, from the center server; and permitting, by the first node apparatus, the received meta-information to be acquired on the overlay network.